Ms Nic Dhomhnaill, who was suffering from an illness at the time of the relationship, said she did not believe the criminal justice system had the necessary respect for victims.

The facts of the case emerged only when Hustveit wrote to his former partner stating he had been using her "body for my gratification" for nearly a year.

The Norwegian man, previously of Leo Street, North Circular Road, Dublin, pleaded guilty at the Central Criminal Court to one count of rape, and one count of sexual assault, between 2011 and 2012.

Mr Justice Patrick McCarthy said the most significant features of the case were the deceit, the repetition of the offences, and the effect on the victim.

Ms Nic Dhomhnaill said that it had taken two years to fully comprehend the magnitude of Hustveit's crimes.

"I'm left grappling with the knowledge that someone I trusted violated that trust regularly. I've lost everything you can claim to have or be. Above all, I've lost my sense of identity and self-worth," she added.

She first met Hustveit in a bar in Dublin city centre in 2011. They began a relationship, and moved in together that year. But she had problems with his use of pornography.

In 2012 she woke up to find herself wet with what she believed to be semen.

She confronted Hustveit who admitted he had had sex with her while she slept. She told him that it was a problem, but the relationship continued.

A few weeks later she woke with the feeling that she had been penetrated to find him masturbating and watching pornography on his laptop beside her in bed.

Hustveit later admitted that he had regularly raped and sexually assaulted her in her sleep, often while she was under the influence of medication. The relationship ended. In a subsequent email exchange between the victim and Hustveit, he made detailed admissions including raping her up to 10 times and touching her in her sleep up to three times per week throughout their relationship.

These emails became the basis of a garda investigation in June 2012 and his computer was seized.

In the email he admitted that he had raped her, saying: "I guess it must be under 10 times."

He also attempted to explain his behaviour, saying: "It is really difficult. I did it for short-term gratification. I convinced myself it was a victimless crime because you were asleep."

He continued: "I didn't want to hurt you, I just wanted to come. I used the fact I wasn't allowed watch porn or masturbate as an excuse. Now I've written this, you can have me prosecuted. I hope you won't."